Major portions of the work in each of the component projects require purified recombinant proteins and synthetic peptides. In addition, three of the four projects will be analyzing protein-protein interactions. The purpose of this Core is to provide access to a central facility for production, purification, and characterization of such proteins. In addition, the Core Unit will provide expertise to the project leaders in configuring Surface Plasmon Resonance (SPR) technology for real-time measurements of protein0protein interactions. This Core Unit will perform prokaryotic expression and purification of recombinant proteins. In addition, when post-translationally modified proteins (e.g., small GTP-binding proteins) are desired, a baculovirus- based expression system will be utilized. The Core will provide facilities for production of cDNA or baculovirus constructs, the fermentations, and purification and chemical characterization of the recombinant proteins by mass spectroscopy.